Fact Sheet 1

GREENHOUSE EFFECT

Greenhouses are used to provide warm places for fruit, vegetables and flowers to grow when it’s too cold for them to grow outside. Greenhouses are covered in glass or plastic which allows light energy from the sun to come in. A lot of the light energy is absorbed by plants and soil and changed into heat energy. Much of the heat is trapped inside which increases the temperature inside the glasshouse, allowing plants to grow.

However, human activities are changing the greenhouse effect. Using coal-fired power plants releases large amounts of carbon dioxide into the atmosphere. Driving cars that run on petrol also puts more carbon dioxide into the air. Keeping large numbers of livestock, such as cattle, can also be harmful because they release lots of extra methane gas into the atmosphere.

All these extra greenhouse gases result in more heat being trapped around the earth. We call this process the enhanced greenhouse effect. When this process causes a long-term rise in the average temperature of the earth we call it global warming.

The earth could be thought of as being like a very large greenhouse. But instead of glass or plastic to keep the heat in, we have gases like water vapour, carbon dioxide and methane in the atmosphere. The sun shines through these gases and gives us light and warmth. These greenhouse gases stop some of the heat from escaping back out into space, making it warm enough for plants, animals and humans to live on earth. Without the greenhouse gases to trap some of the heat on earth, the average surface temperature of the earth would be below 0 degrees Celsius.

Available as:

PDF – Fact Sheet 1

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